A phenomenon wherein a single phenotype or genetic disorder may be caused by mutations of several genetic loci or allele.

A transmission pattern of inheritance which is manifested in the heterozygous state, wherein at least one parent of an index case is usually affected, both males and females are affected and both can transmit the condition.

This pattern of inheritance occur when BOTH of the alleles at a given gene locus are mutants, wherein the parents are not affected, but offspring have 1 in 4 chance (25%) of being affected.

Autosomal recessive(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.229

25

Pattern of inheritance wherein the disorder is transmitted by heterozygous female carriers only to 50% of the sons. An affected male does not transmit the disorder to sons but all daughters are carriers.

A collection of disorders caused by defects in collagen synthesis or structure, characterized by hyperextensible skin and joint hypermobility, rupture of internal organs and poor wound healing.

This autosomal recessive inborn error of metabolism is characterized by inability to convert phenylalanine to tyrosine, strong mousy or musty odor of urine and sweat, decreased pigmentation of hair and skin, eczema, seizures and mental retardation.

Phenylketonuria (PKU)(TOPNOTCH)

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This autosomal dominant disorder is caused by a mutation in the gene that specifies the receptor for LDL, impairing the intracellular transport and catabolism of LDL.

Tay-Sachs disease(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.236

Gaucher disease(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.238

42

What do you call the pathognomonic cell characterized by "wrinkled tissue paper" cytoplasmic appearance.

Gaucher cell(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.238

43

These disorders result from the accumulation of mucopolysaccharides in many tissues including the liver, spleen, heart, blood vessels, brain, cornea and joints. Affected patients have coarse facial features.

Mucopolysaccharidoses(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.238

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Mucopolysaccharidosis characterized by corneal clouding, coronary arterial and valvular depositions, which occurs due to deficiency of a-L-iduronidase, leading to accumulation of dermatan and heparan sulfate.

Hurler syndrome(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.239

45

An X-linked mucopolysaccharidosis which is due to a deficiency of L-iduronate sulfatase. Symptoms are similar to Hurler sundrome, but without corneal clouding.

Deletion of genes from this chromosome gives rise to DiGeorge and velocardiofacial syndromes.

The q from 22q11.2 refers to ________.

Syndrome defined as male hypogonadism that develops when there are at least two X chromosomes and one or more Y chromosomes.

Klinefelter syndrome(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.246

70

Syndrome manifested by a eunochoid body habitus, reduced facial, body and pubic hair, gynecomastia, testicular atrophy, decreased serum testorerone and incresed urinary gonadotropin levels. It is the most common cause of hypogonadism in males.

Klinefelter syndrome (TOPNOTCH)Robbins Basic Pathology, 8th Ed p.246

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Most common chromosomal derangement in Klinefelter syndrome.

47XXY(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.246

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Syndrome which results from the partial or complete monosomy of the short arm of the X chromosome.

Turner syndrome(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.247

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Inheritance associated with mitochondrial DNA.

Maternal inheritance(TOPNOTCH)

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Neurodegenerative disease which manifests as progressive bilateral loss of central vision that leads to blindness. This is the prototypical disorder of mutations in mitochondrial genes.

Angelman syndrome(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.251

These represent primary errors of morphogenesis due to an intrinsically abnormal developmental process.

Malformations(TOPNOTCH)

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These represent primary errors of morphogenesis due to an intrinsically abnormal developmental process.

Malformations(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.254

83

These result from secondary destruction of an organ or body region that was previously normal in development, due to an extrinsic disturbance in morphogenesis.

Disruptions(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.254

84

These are due to generalized compression of the growing fetus by abnormal biomechanical forces, for example uterine constraint.

Deformations(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.254

85

This refers to multiple congenital anomalies that result from secondary effects of a single localized aberration in organogenesis. The initiating event may be a malformation, deformation or disruption.

Sequence(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.254

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This refers to the presence of several defects that cannot be explained on the basis of a single localizing initiating error in morphogenesis.

Multiple petechiae of the thymus, visceral and parietal pleura and epicardium, congested lungs with vascular engorgement with or without pulmonary edema.

Results from antibody-induced hemolytic disease in the nnewborn that is caused by blood group incompatibility between mother and fetus, leading to edema fluid accumulation.

Immune Hydrops(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.261

102

Erythroid precursors with large homogenous, intranuclear inclusions and a surrounding peripheral rim of residual chromatin can be seen in the bone marrow aspirate of an infant infected with this virus. This leads to development of non-immune hydrops.

Parvovirus B19(TOPNOTCH)

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Isolated postnuchal fluid accumulation in fetuses with hydrops.

Cystic hygroma(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.261

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A lethal condition characterized by generalized edema of the fetus.

Hydrops fetalis(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.261

105

Increased hematopoietic activity leading to the presence of large number of immature red cells, including reticulocytes, normoblasts and erythroblasts. Characteristic finding in fetal anemia-associted hydrops.

Erythroblastosis fetalis(TOPNOTCH)

106

Primary gene defect in cystic fibrosis.

Lungs with extensive mucous plugging and dilated tracheobronchial tree. Pancreatic ducts dilated and plugged with eosinophilic mucin, atrophic parenchymal glands replaced by fibrous tissue. Hepatic steatosis, Azoospermia and infertility are some of the features of this disease.

Cystic fibrosis(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.262

108

Patients with cystic fibrosis are prone to developing infections caused by these three organisms.

Homer-Wright pseudorosettes(TOPNOTCH)

Most common germ cell tumors of childhood,associated with meningocoele and spina bifida.

Tumor of the adrenal medulla composed of small, primitive-appearing cells with dark nuclei, scant cytoplasm, and poorly defined cell borders growing in solid sheets within a finely fibrillar matrix. Rosettes can be found in which tumor cells are concentrically arranged about a CENTRAL SPACE FILLED with neuropil.

Ganglioneuroma(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.270

Disseminated neuroblastoma with multiple cuteaneous metastases with deep blue discoloration to the skin.

This tumor is composed of small, round cells with large hyperchromatic nuclei and scant cytoplasm, with characteristic structures consisting of clusters of cuboidal or short columnar cells arranged around a CENTRAL LUMEN. The nuclei are displaced away from the lumen, which appears to have a limiting membrane.

Components of the WAGR syndrome.

Presents grossly as a large, solitary, well-circumscribed mass. On cut-section, tumor is soft, homogenous, and tan to gray, with occasional foci of hemorrhage, cystic degeneration and necrosis.

Wilm's tumor(TOPNOTCH)Robbins Basic Pathology, 8th Ed p.272

128

Microscopically, a combination of blastemal, stromal and epithelial cell types is observed. (Triphasic combination) Blastemal components described as sheets of small blue cells with few distinctive features. Stromal cells are fibrocytic or myxoid in nature. Epithelial cells take the form of abortive tubules or glomeruli.